Dark blood is signs of internal bleeding. Deff call your doctor or even hospital. If it was light red and just a small amount of it, out could be irritation of your esophagus/throat from throwing up. It happen to me a few times in my beginning weeks. I was violently sick at all hours of the day and night for almost 4 months. With the medicine try lemon water and spermint mints it helps reduce neasua greatly, at least for me. If you are really concerned always call your doctor just to be sure a simple phone call normally puts all your troubles at ease , sociality if you are a first time mom
There are different pills the doc can prescribe you if the ones you have are not working. Personally i take zofran and must take them correctly or they will not work. Your throat is probably irrated therefore causing the blood in your vomit. Try ginger ale and crackers to settle your stomach.